Carbazole derivatives

ABSTRACT

NOVEL 3,6-BIS-BASIC ALKANES OF CARBAZOLE, THEIR PREPARATION AND USE FOR THE PREVENTION AND INHIBITION OF VIRAL INFECTIONS ARE DISCLOSED.

United States Patent 3,833,596 CARBAZOLE DERIVATIVES William L.Albrecht, Cincinnati, Ohio, and lfohert W.

Fleming, Ann Arbor, Mich., assignors to Richardson- Merrell Inc., NewYork, N.Y. N0 Drawing. Filed Dec. 21, 1972, Ser. No. 317,149 Int. Cl.C07d 29/28 US. Cl. 260293.61 4 Claims ABSTRACT OF THE DISCLOSURE Novel3,6-bis-basic alkanes of carbazole, their preparation and use for theprevention and inhibition of viral 1nfections are disclosed.

FIELD OF THE INVENTION This invention relates to new organic chemicalcompounds, to their preparation, and to pharmaceutical compositionscontaining such compounds. The compounds de scribed herein are antiviralagents which are useful in inactivating or inhibiting viruses by theiradministration to either an infected or a non-infected host.

BACKGROUND OF THE INVENTION There is a growing body of information thatviruses play a vital role in a broad range of diseases, some of whichrepresent the most serious of mans ills. Arthritis, juvenile arthritis,diabetes, Hodgkins disease and various immunological diseases anddegenerative diseases of the central nervous system have been linked toviruses as the causative agents.

At present, the control of virus infections is primarily achieved bymeans of immunization vaccines. For example, poliomyelitis, smallpox,measles and influenza are well recognized diseases in which virusvaccines have proven effective. In general, however, virus vaccines havehad only a moderate success in animal prophylaxis. Each vaccine actsprimarily against a specific virus and is not heterophilic in theprotection it offers. Hence, vaccines have not provided a practicalsolution against the wide array of infectious viruses, even when limitedas for example, solely to respiratory viruses.

One approach to the control of virus-related diseases and, particularlyto the spread of such virus diseases, has been to search for medicinalagents or chemotherapeutic agents which are capable of inhibiting thegrowth of viruses, thereby preventing the spread of disease as well aspreventing further damage to cells and tissues of the animal host whichhave not as yet been infected. Hcretofore, only a limited number ofvirus infections such as smallpox, Asian influenza and herpes keratitishave been prevented by chemical antiviral agents. Sulfonamides andantibiotics which have revolutionized the treatment of bacterialinfections have substantially no effect upon virus infections. Certaininfections caused by large viruses, such as lymphogranuloma venereum,psittacosis and trachoma have been successfully treated usingantibiotics and sulfa drugs. However, the majority of infections havenot been responsive to attack by chemotherapeutic agents. Thus, it canbe seen that there is a need for new chemotherapeutic agents which areeffectiveagainst a broad range of virus diseases, and which at the sametime, are non-toxic to the host.

As a result of a long series of investigations, applicants havediscovered a novel class of 3,6-bis-basic alkane derivatives ofcarbazole which are particularly useful as antiviral agents. Thesecompounds are effective against a Wide spectrum of virus infections andare useful in treating such infections both prophylactically andtherapeutically. To applicants knowledge, the compounds described and3,833,596 Patented Sept. 3, 1974 claimed herein are novel compoundswhich have not previously been described nor reported in the literature.The instant compounds possess a wide spectrum of antiviral activity invarying degrees which could not have been predicted from a knowledge ofthe present state of the art.

SUMMARY OF THE INVENTION This invention relates to new derivatives ofcarbazole, to their preparation and to their use as pharmaceuticalagents. More particularly, the compounds of the present invention are3,6-bis-basic alkanes of carbazole which are useful as antiviral agents.Still more particularly, the compounds of the present invention may berepresented by the following general formula:

8' 1 e 7 l l 2 6 s /N AWWA N\ .R (I) R, wherein A is a straight orbranched alkylene chain having from 2 to 6 carbon atoms; R and R areeach selected from the group consisting of hydrogen, lower alkyl havingfrom 1 to 6 carbon atoms, cycloalkyl having from 3 to 6 carbon atoms,alkenyl having from 3 to 6 carbon atoms in which the unsaturation is ina position other than in the 1-position of the alkenyl group, and when Rand R are taken together with the nitrogen atom to which they areattached represent the pyrrolidinyl, morpholino or piperidino radical; Ris hydrogen or lower alkyl having from 1 to 4 carbon atoms; and theirpharmaceutically acceptable acid addition salts.

The 3,6-bis-basic alkanes of carbazole of the present invention areprepared by the reduction of the corresponding 3,6-bis-basic ketones ofcarbazole with hydrazine in the presence of a strong base is illustratedby the following general reaction scheme:

in the above reaction, the symbols A, R, R and R have the valuespreviously assigned to them, and B is a straight or branched alkylenechain having from 1 to 5 carbon atoms. The 3,6-bis-basic ketones ofcarbazole (II) useful as starting materials in the above reaction aredisclosed as preferred compounds in copending application Ser. No.374,350 filed June 28, 1973, which is a continuation of Ser. No. 57,780,filed July 23, 1970, now abandoned.

To achieve an antiviral effect the compounds of this invention arepreferably administered to a host using a variety of compositions. Suchcompositions may be administered either prior to infection, as ,with aprophylactic use or treatment, or they may betherapeuticallyadministered subsequent to infection, as with a curative use ortreatment. Additionally, the compounds of this invention 3 result thatthe various disease symptoms characteristic of the pathogenic virusinfection are no longer present.

DETAILED DESCRIPTION OF THE INVENTION As can be seen from the abovegeneral formula (I), the basic alkane groups substituted on thecarbazole ring consist of a basic amino function separated from thecarbazole nucleus by an alkylene chain of prescribed length. It is alsoapparent that one of the basic alkane groups is located on each of thebenzenoid portions of the carbazole ring.

The alkylene chain separating the amino function from the tricyclic ringconsists of from 2 to 6 carbon atoms and represents either a straight orbranched alkylene chain. Additionally, each of the alkylene groups maybe the same or different; preferably, however, both groups are the same.Illustrative of the various alkylene groups which are represented by thesymbol A are the: ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene,1,6-hexylene, 2-methyl-1,4-butylene and 3-methyl-1,5-pentylene radicals.

The basic amino function can be a primary, secondary or a tertiary aminogroup. Preferably, each of the amino groups represented by the symbol isa tertiary amino group. The symbols R and R represent either hydrogen ora lower alkyl group. The term lower alkyl as used with regard to theamino groups relates to groups having from 1 to 6 carbon atoms.Illustrative of such groups can be mentioned straight or branched chainalkyl radicals such as: methyl, ethyl, 3-propyl, isopropyl, n-butyl,sec-'butyl, isoamyl, n-pentyl and n-hexyl. When R and R each representlower alkyl, 9. preferred subgenus is formed.

Each R and R of the basic amino function also represents a cycloalkylgroup having from 3 to 6 carbon atoms. Such groups include thecyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl radicals.

The symbols R and R also represent an .alkenyl group, having from 3 to 6carbon atoms. In addition, the unsaturation present in this group mustbe in a position other than the 1-position inasmuch as any unsaturationat this point is readily hydrolyzable. Illustrative of such groups arethe allyl, 3-butenyl and the 4-hexenyl radicals.

Rand R also represent various saturated, monocyclic, heterocyclicradicals when taken in conjunction with the amino nitrogen atom to whichR and R is attached. Typical of such heterocyclic groups are thepyrrolidinyl, piperidino and morpholino radicals. Compounds containingsuch groups are readily prepared and typify saturated, monocyclic,heterocyclic radicals which are generally useful in lieu of the diloweralkylamino groups present in the compounds of this invention.

Illustrative of specific base compounds of the present inventionrepresented by general formula (I) are:

3, 6-bis(4-dimethylaminobuty1)carbazole,

3,6-bis(5-piperidinopentyl)carbazole,

3,G-bis(4-diethylaminobutyl)-9-methylcarbazole,

3 ,6-bis 4-diethylaminobutyl) -9-ethylcarbazole,

9-ethyl-3,6-bis(4-piperidinobutyl)carbazole,

3 ,6-bis (S-dimethylaminopentyl -9-ethylc arb azole,

3,6bis(S-diethylamino 3-methylpentyl)-9-ethylcarbazole,

9-ethyl-3,6-bis(4-morpholinobutyl)carbazole,

9-ethyl-3 6-bis 5 pyrrolidinopentyl) carb azole,

'3 ,6-bis (4-diallylar'ninobu tyl) -9-ethylcarb azole,

3,6-bis(4-diethylaminobutyl)-9-propylcarbazole.

The expression .fp'harmaceutically acceptable acid additionsaltsencompasses any non-toxic organic or inorganic acid addition salts ofthe base compounds represented by either formula (I) or (II).Illustrative inorganic acids which form suitable salts includehydrochloric, hy-

drobromic, sulfuric and phosphoric acids and acid metal salts such assodium monohydrogen orthophosphate and potassium hydrogen sulfate.Illustrative organic acids which form suitable salts include the mono,di and tricarboxylic acids, for example, acetic, fumaric, malic,tartaric, citric, ascorbic, maleic, hydroxymaleic, benzoic,hydroxybenzoic, phenylacetic, cinnamic, salicyclic, 2-phenoxybenzoic,and sulfonic acids such as methane sulfonic acid and l-hydroxyethanesulfonic acid. Either the mono or the di-acid sa'lts can be formed, andsuch salts can exist in either a hydrated or a substantially anhydrousform.

In general, the 3,6-bis-basic alkanes of carbazole described and claimedherein are prepared by reducing the corresponding 3,6-bis-basiccarbazole ketones under modified WolfiF-Ki-shner conditions. The,3,6-bis-basic carbazole ketones are, in turn, readily prepared via aFriedel-Crafts halo-acylation of carbazole. The resulting'3,6-bis(whaloalkanoyl) carbazole derivatives can be aminated under avariety of conditions using either ammonia, a primary or a secondaryamine. For example, the carbazole can be heated with a large excess ofamine, the excess amine serving as the reaction medium and hydrohalideacceptor. Alternatively, the carbazole derivative may be heated with theamine in a suitable solvent such as toluene, dioxane ordimethylformamide to effect condensation. Specific illustrations for thepreparation 'of 3,6-bis-basic carbazole ketones are more fully disclosedin copending application Ser. No. 374,350, filed June 28, 1973, which isa continuation of Ser. No. 57,780, filed July 23, 1970, now abandoned.

The reduction of the 3,6-bis-basic ketones of carbazole is bestaccomplished by heating the carbazole ketones with hydrazine in thepresence of a basic catalyst. Basic catalysts which may be employedinclude either sodium or potassium hydroxide. Additionally,sodium-methoxide and ethoxide can be usefully employed and are equallyoperative in preparing the compounds of this invention.

The reduction with hydrazine proceeds through the formation of theintermediate hydrazone of the bis-basic ketone. The presence of water isto be avoided in order to prevent azine formation via the condensationof the intermediate hydrazone with the bis-basic carbonyl startingmaterial. In order to achieve complete reduction, the reaction isconducted at an elevated temperature of from about to C., for a periodranging from 12 to 48 hours. Conveniently, the reaction is conducted atthe refiux temperature of a high-boiling solvent, such as a higheraliphatic alcohol or polyglycol. In the practice of the presentinvention applicants prefer to use diethylene glycol as the solvent anda reflux period about 16 hours.

The 9-substituted lower alkyl carbazoles are obtained in almostquantitative yield by the action of a concentrated aqueous solution ofsodium or potassium hydroxide upon an acetone solution of carbazoleusing an appropriate lower alkyl iodide or sulfate. Thus, for example,when an acetone solution of carbazole and methyl sulfate is mixed withan aqueous solution of sodium hydroxide, vigorously shaken and pouredinto water, an almost quantitative yield of N-methylcarbazole isobtained.

The compounds of the present invention are antiviral agents. Preferablythey are administered to an animal host to prevent or inhibit viralinfections. The term'host refers to any viable biological material orintact animal including humans which is capable of inducing theformation of interferon and which serves as a support means for virusreplication. Thehost can be of animal or mammalian origin.Illustratively such hosts include birds, mice, rats, guinea pigs,gerbils, ferrets, dogs, cats, cows, horses and humans. Other viablebiological material such as used in the production of vaccines rr't ayalso act as a host. Thusftissue cultures prepared from organ tis'srn'esuch as mammalian kidney or lungtis'sue, as well as tissue culturesprepared from embryo tissue, such as from amniotic cells or chickallantoic fluid, have been found to be useful hosts. a

The treatmentofvirus infectionsfor purposes of the present inventionencompasses both the prevention and the inhibition of characteristicdisease symptoms in a mammalian hostsusceptible to invasion by apathogenic virus. Illustrative of mammalian virus'infections which canbe prevented. or inhibited by the administration of the compounds -ofthe present invention are infections caused by picornaviruses, such asencephalomyocarditis virus; myxoviruses, such as influenza A (lap/ 305)virus; arboviruses, such asSemliki forest virus; the herpes group ofviruses, including herpes simplex and the poxviruses, as for examplevaccinia IHD. Thus, for example, the compounds of the present inventionwhen administered orally or subcutaneously to mice in varying doseseither shortly prior 'or subsequent to a fatal inoculation of aneurotropic virus such as encephalomyocarditis virus, having a LDanywhere from 5 to 50, delay or prevent completely the onset of death.Salts of these compounds are generally administered in compositionscontaining a 0.15% aqueous hydroxyethylcellulose vehicle, whereas thefree base compounds are generally administered in compositionscontaining a aqueous surfactant vehicle in order to help solubilize thecompound. In general, ten mice are used for each treated group with anadditional 20 mice serving asal control group. At thetime ofadministration the test virus is titrated, in order to determine thepotency or LD for the particular virus pool used as a challenge. Thecontrolanimals are givena placebo containing the identical volume ofvehicle without, of course, the active ingredient. Because of the lethalnature of the test system employed, the-antiviral nature of the testcompound is dramatically illustrated by a side by side comparison of thesurvival tim e of treated animals with the untreated control group ofanimals. Respiratory viruses, such as influenza A Gap/305) virus, whichare also lethal to the test animals employed, are administered viaintranasal-instillation. Animals infected in this manner have the activeingredients administered in the-same manner as the test virus, and againa side by side comparison is made of the survivors of the animalstreated with the untreated control animals.

Inexplicably, a mouse fatally infected with encephalomyocarditis orinfluenza virus occasionally survives without further treatment. Thismay be the result of a prior, interferon-inducedinfection in the mouse,or perhaps due to some geneticfactor or other natural defense mechanismnot 'presently'understood. For this reason the control group selectedisof sufficient size as to statistically reduce the'infiuence of such achance survivor upon the test results to a negligible amount.

The vacinia test virus is typical of the dermatotrophic type viruseswhich respond to treatment with compositions containing the compound ofthe instant invention. The vaccinia virus generally products a non-fatalinfection in mice, producing characteristic tail lesions when the virusis subcutaneously administered to the tail of the mouse. The instantcompounds are administered either orally or subcutaneously either priorto or subsequent to the vaccinia infection. Tail lesions aresubjectively scored on the eighth day following infection againstuntreated animals which serve as a control group. The compounds of thepresent inventionhave'been found to be effective in varying degreesagainst one or all of these test viruses.

. The mode of activity of the active ingredients of the presentinvention is not rigorously defined. Inter alia, the compounds of thepresent invention may induce the formation of interferon in a viablehost. Interferon is a biological substance of unknown chemicalstructure, presumably proteinaceous innature, which is produced by hostcells in response to a viral infection. The interferon so produced actsto induce a virus inhibiting substance, which inhibits in some'iyetunknown manner'the intracellular replication of the virus withoutappearing to have any inass-r596 6 1 activation effect per se upon thevirus itself. A few of the viruses susceptible to interferon replicationinhibition are described in Horsfall and Tamm, Viral and RickettsialInfections of Man, 4th 'Edition (1965), J. B. Lippincott Company, pp.328-9.

As previously indicated, the compounds of the presen invention may beprophylactic-ally administered in order to prevent the spread ofcontagious viral diseases, or they may be therapeutically administeredto a host already infected intended for their curative effect. Whenadministered prophylactically, it is preferred that the administrationbe made within 0 to 96 hours prior to the infection of the host animalwith a pathogenic virus. When the compounds of the present invention areadministered for their curative effect, it is preferred that they areadministered within about 1 or 2 days following infection of the host inorder to obtain the maximum therapeutic effect.

The dosage to be administered will be dependent upon such parameters asthe particular virus for which either treatment or prophylaxis isdesired, the species of animal involved, its age, health, weight, theextent of infection, concurrent treatment, if any, frequency oftreatment and the nature of the effect desired. A daily dose of theactive ingredients will generally range from about 0.1 mg. to about 500mg. per kg. of body weight. Illustratively, dosage levels of theadministered active ingredients for intravenous treatment range fromabout 0.1 mg. to about 10 mg. per kg. of body weight; intraperitonealadministration range from about 0.1 mg. to about 50 mg. per kg. of bodyweight; subcutaneous administration range from about 0.1 mg. to about250 mg. per kg. of body weight; oral administration may be from about0.1 mg. to about 500 mg. per kg. of body weight, intranasal instillationrange from about 0.1 mg. to about 10 mg. per kg. of body weight; and foraerosol inhalation therapy, the range is generally from about 0.1 mg. toabout 10 mg. per kg. of body weight.

The novel compounds described herein can also be administered in variousdilferent dosage unit forms, e.g., oral compositions such as tablets,capsules, drages, lozenges, elixirs, emulsions, clear liquid solutionsand suspensions; parenteral compositions such as intramuscular,intravenous or intradermal preparations; and topical compositions, suchas lotions, creams or ointments. The amount of active ingredientcontained in each dosage unit form will, of course, vary widelyaccording to the particular dosage unit employed, the animal host beingtreated, and the nature of the treatment, i.e., whether prophylactic orthera peutic in nature. Thus, a particular dosage unit may contain fromabout 2.0 mg. to over 3.0 g. of active ingredient in addition to thepharmaceutical excipients contained therein. The novel compoundsdescribed herein can be employed in conjunction or admixture withadditional organic or inorganic pharmaceutical excipients. Suitablesolid excipients include gelatin, lactose, starches, magnesium stearateand petro-latum. Suitable liquid excipients include water and alcoholssuch as ethanol, benzyl alcohol and the polyethylene alcohols eitherwith or without the addition of a surfactant. In general, the preferredliquid excipients particularly for injectable preparations, includewater, saline solution, dextrose and glycol solutions such as an aqueouspropylene glycol or an aqueous solution of polyethylene glycol. Liquidpreparations to be used as sterile injectable solutions will ordinarilycontain from about 0.5% to about 25% by weight, and preferablyv fromabout 1% to about 10% by weight, of the active ingredient in solution.In certain topical and parenteral preparations, various oils areutilized as carriers or excipients. Illustrative of such oils aremineral oils, glyceride oils such as lard oil, cod liver oil, peanutoil, sesame oil, corn oil and soybean oil.

A preferred method of administration for the compounds of the presentinvention is orally either in a solid dose form such as a tablet orcapsule, or in a liquid dose form such as an elixir, suspension,emulsion or syrup.

Ordinarily the active ingredient comprises from about 0.5% to about 10%by weight in an oral liquid composition. In such compositions, thepharmaceutical carrier is generally aqueous in nature, as for example,aromatic water, a sugar-based syrup or a pharmaceutical mucilag'e. Forinsoluble compounds suspending agents may be added as well as agents tocontrol viscosity, as for example, magnesium aluminum silicate orcarboxymethylcellulose. Buffers, preservatives, emulsifying agents andother excipients can also be added.

For parenteral administration such as intramuscular, intravenous orsubcutaneous administration, the proportion of active ingredient rangesfrom about 0.05% to about 20% by weight, and preferably from about 0.1%to about 10% by weight of the liquid composition. In order to minimizeor eliminate irritation at the site of injection, such compositions maycontain a non-ionic surfactant having a hydrophile-lipophile balance(HLB) of from about 12 to about 17. The quantity of surfactant in suchfOrmulatiOns ranges from about to about 15% by weight. The surfactantcan be a single component having the above-identified HLB, or a mixtureof two or more components having the desired HLB. Illutrative ofsurfactants useful in parenteral formulations are the class ofpolyoxyethylene sorbitan fatty acid esters as, for example, sorbitanmonooleate and the high molecular weight adducts of ethylene oxide witha hydrophobic base, formed by the condensation of propylene oxide withpropylene glycol. The concentration of active ingredient contained inthese various parenteral dosage unit forms varies over a broad range andcomprises anywhere from about 0.05% to about 20% by weight of the totalformulation, the remaining component or components comprising excipientspreviously mentioned.

The active ingredients of the present invention can also be admixeddirectly with animal feeds or incorporated into the drinking water ofanimals. For most purposes, an amount of active ingredient is used whichprovides from about 0.000l% to about 0.1% and preferably, from about0.001% to about 0.02% by weight of the active ingredient based upon thetotal weight of feed intake. The active ingredients can be admixed inanimal feed concentrates, suitable for. use by farmers or livestockgrowers for incorporation in appropriate amounts with the final animalfeeds. These concentrates ordinarily comprise from about 0.5% to about95% by weight of the active ingredient compounded with a finely dividedsolid carrier or flour, such as wheat, corn, soybean or cottonseedflour. Depending upon the particular animal to be fed, nutrients andfillers may also be added such as ground cereal, charcoal, fullersearth, oyster shells and finely divided attapulgite or bentonite.

The active ingredients of the present invention can be packaged in asuitable pressurized container together with an aqueous or volatilepropellant for use as an aerosol. A suitable discharge valve is fittedto an opening in the container from which the active ingredients may beconveniently dispensed in the form of a spray, liquid, ointment or foam.Additional adjuvants such as co-solvents, wetting agents andbactericides may be employed as necessary, Normally, the propellant usedis a liquified gaseous compound, preferably a mixture of low molecularWeight lustrated by means of the following specific examples:

EXAMPLE I 3,6-Bis(4-chlorobutyryl)-9-ethylcarbazole To a solution of78.0 g. (0.4 mole) of 9-ethylcarbazole and 141 g. (1.0 mole) of4-chlorobutyry1 chloride in l liter of methylene chloride, which hasbeen previously chilled to 0 Cl, is addedportionwise.l27.0g. (0.95 mole)of aluminum chloride. The mixturezis stirred'at room temperature for'-l6.hours, and-wthe resulting complex is'decomposed with a concentratedhydrochloric acid-ice mixture. The. organiclayer-is separated,washedwith water, dried over magnesium sulfate and'pentaneaddedtoprecipitate the desired product. Recrystallization from ac'etonefollowed by a recrystallizationfrom-an acetone methanol solution resultsin the-formation of 3,6-bis. .(4-chloro butyryl)-9-ethylcarbazole, m.p.l068 C.;

x523 259; and Ea..."103'o;

EXAMPLE II 9-Ethyl-3,6-bis(4-piperidinobutyryl) carbazole. I

dihydrochloride hemihydrate A mixture of 19.5 g. (0.048 mole) of9-ethyl-3,6-bis- (4-chlorobutyryl)carbazole, 34.0 g. (0.4 mole)of-piperidine, 2.0 g. of potassium'iod'ide and 250 m1. of p-dioxane isheated with stirring at the re'fiux temperature for a period of 68 hoursand filtered while hot. Upon cooling, "the mixture is diluted with 500ml. of water, and the resulting semi-solid which forms is dissolved inether. The ether solution is washed repeatedly with water, driedov e'rmagnesium sulfate and treated with an ethereal-hydrochloric acidsolution resulting in the formationof9-ethy1-3,6-bis(4-piperidinobutyryl)carbazole' dihydrocliloridehemihydrate, which isrecrystallized from methanol ethyl acetate solution to yield a producthaving amp. 138-42 C.;

A232? 258; and Ei'f' 699.

Following the same procedure but substituting diethylamine,dimethylamine, dibutylaminev or morpholine for the piperidine aboveresults in the preparation-of3,6-bis(4,diethylaminobutyryl)-9-ethylcarbazole 'dihydrochloride, 7 a 19-ethyl-3,6-bis(4-dirnethylbutyryl)carbazole dihydrochloride, I9-ethyl-3,6-bis(4-dibutylaminobutyryl) carbazole dihy-I drochloride, andI 9-ethyl-3,6-bis(4-morpholinobutyryl)carbazole dihydrochloride,

respectively. EXAMPLE III 9-Ethyl-3,6-bis(4-piperidinobutyl)carbazoledihydrochloride- Theremaining sodium hydroxide is added-in incrementsand the reaction mixture heated with continued stirring to a temperatureof. for a period of 16 hoursQThe reaction mixture is cooled to' roomtemperature, pouredlinto 700 ml. of an ice-water mixture, extracted withether, .and the combined ether extracts driedandacidified withhydrochloric acid. The product whichprecipitates is recrystallized twotimes from a methanol-ethyl acetate solution xi 2: a Bit... 91s.

EXAMPLE IV 3,6-Bis-(4-piperidinobutyl)carbazole dihydrochlorideEmpolying-the procedure of Example III but replacing 9 7 ethyl-3,6-bis(4l piperidinobutyryl)carbazole dihydrochloride hemihydrate with'anequivalent amount of 3,6- bis(4-piperidinobutyryl)carbazolej results inthe preparation of 3,6-bis(4-p'iperidinobutyl)carbazoledihydrochloride..

' l EXAMPLE V 3,6-Bis(4-diethyl aminobutyl) -9-ethylcarbazole pdihydrochloride A solution of 11.0 g. (0.02 mole) of3,6-bis(4-diethylaminobutyryl)-9-ethylcarbazole dihydrochloride and 25ml. of an 85% aqueous hydrazine'hydrate solution is dissolved in 200 ml.of ethylene glycol and heated to a temperature of 165 C. fora period of18 hours. The reaction mixture is cooled and-diluted with waterwhereupon the free base of the desired compound separates as an oil. Theproduct is separated by decantation, washed with water, dissolved indiethyl ether and the ethereal solution dried over magnesium sulfate.The dried solution is concentrated to a small volume and placed on analuminum oxide chromatographic column and eluted with methylenechloride. The eluate is converted to its hydrochloride salt andcrystallized from a methanol-ethyl acetate solution. Recrystallizationfrom acetone with two additional recrystallizations from a methylenechloride-acetone solution results in the preparation of3,6-bis(4-diethylaminobutyl)-9-ethylcarbazole dihydrochloride having am.p. 172-4 C.; and

A212? 240; and E}? 907.

EXAMPLE VI Illustration of the antiviral activity of3,6-bis(4-diethylarninobutyl) -9-ethylcarbazole dihydrochloride Thirtymice weighing approximately 12-15 gms. each are divided into two groups,a control group of 20 animals and a test group of 10 animals. All of theanimals are challenged with a fatal dose (6LD of encephalomyocarditisvirus. The test group of animals are tested both prophylactically andtherapeutically using a parenteral composition containing 3,6 bis(4diethylaminobutyl)-9- ethylcarbazole dihydrochloride as the activeingredient dissolved in a solution of 0.15% aqueoushydroxyethylcellulose solution as the vehicle. The composition containsthe active ingredient in an amount such that each dosage contains 0.25ml. which is equivalent to a dose level of 50 mg. per kg. The controlgroup receives a subcutaneous placebo containing the same volume ofvehicle without the active ingredient. Observations over a day periodshow the termination of all the control animals within a period of from4 to 5 days, with the treated group surviving for a statistically longerperiod of time.

EXAMPLE VII Preparation of a capsule formulation An illustrativecomposition for hard gelatin capsules is as follows:

Per capsule, mg. (a) 3,6 bis(4 diethylaminobutyl) 9 ethylcarbazoledihydrochloride 200 (b) Talc 35 powder can be filled as a granulation,slug or compressed tablet directly into the rotary dye or plate mold inwhich the soft gelatin capsule is formed.

EXAMPLE VIII Preparation of a tablet formulation An illustrativecomposition for tablets is as follows:

Per tablet, mg. (a) 3,6 bis(4 dimethylaminobutyl)carbazoledihydrochloride (b) Wheat starch and granulated starch paste (10% w./v.)15 (c) Lactose 33.5 (d) Magnesium stearate 1.5

The granulation obtained upon mixing lactose, starch and granulatedstarch paste is dried, screened and mixed with the active ingredient andmagnesium stearate. The mixture is compressed into tablets weighingmilligrams each.

EXAMPLE 1X Preparation of an oral syrup formulation A 2% weight pervolume syrup of 3,6-bis(5-diethylamino 3 methylpentyl) 9 ethylcarbazoledihydrochloride is prepared by the usual pharmaceutical techniques inaccordance with the following formula:

Grams (a) Finely divided 3,6-bis(5-diethylamino-3-methylpentyl)-9-ethylcarbazole dihydrochloride 2.0 (b)Sucrose 33.3 (c) Chloroform 0.25 (d) Sodium benzoate 0.4 (e) Methylp-hydroxybenzoate 0.02 (f) Vanillin 0.04 (g) Glycerol 1.5

(h) Purified water to 100.0 ml.

EXAMPLE X Preparation of parenteral formulation An illustrativecomposition for a parenteral injection is the following emulsion:

Each 1111. contains Ingredients Amount 50 mg9-ethyl-3,6-bis(4-piperidin0butyl) carbazole 1,000 g.

dihydroehlori e. 100 mg Polyoxyethylene sorbitan monooleate 2.000 g.0.0064 Sodium chloride 0.128 g.

Water for inflection, q.s 20.000 ml- EXAMPLE XI Preparation of dustingpowder formulation The following formulation illustrates a dustingpowder for topical use:

Per kilogram, gm.

(a) 9 ethyl 3,6 bis(4 piperidinobutyl)carbazole dihydrochloride 20 (b)Silica aerogel 980 The dusting powder is prepared by intimately blendingthe ingredients. The resulting mixture is then packaged in suitabledispensing containers.

,1 1 What is claimed is: 1. A 3,6-bis-basic alkane of carbazole havingthe general formula:

wherein A is a straight or branched alkylene chain having from 2 to 6carbon atoms; R and R are each selected from the group consisting oflower alkyl having from 1 to 6 carbon atoms, alkenyl having from 3 to 6carbon atoms in which the unsaturation is in a position other than inthe 1-position of the alkenyl group, and when R and R are taken togetherwith the nitrogen atom to which they are attached represent thepyrrolidinyl, morpholino or piperidino radical; R is hydrogen or loweralkyl having from 1 to 4 carbon atoms; and the pharmaceuticallyacceptable acid addition salts thereof.

2. A compound of claim 1 wherein each R and R is a lower alkyl grouphaving from 1 to 6 carbon atoms.

Reference s Cited STA ES, NTS

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OTHER Shirley: Organic Chemistry, Holt, Rinehart and Winston, New York(1964),p. 1 A I G. THOMAS TODD, prip gry'n a iir r U.s, 'b1. X.R,';260246 B, 315; 424-248, 267,274

